Ivabradine in Heart Failure: The Representativeness of SHIFT (Systolic Heart Failure Treatment With the IF Inhibitor Ivabradine Trial) in a Broad Population of Patients With Chronic Heart Failure

Pacemaker Channels and the Chronotropic Response in Health and Disease

Loss or dysregulation of the normally precise control of heart rate via the autonomic nervous system plays a critical role during the development and progression of cardiovascular disease-including ischemic heart disease, heart failure, and arrhythmias. While the clinical significance of regulating changes in heart rate, known as the chronotropic effect, is undeniable, the mechanisms controlling these changes remain not fully understood. Heart rate acceleration and deceleration are mediated by increasing or decreasing the spontaneous firing rate of pacemaker cells in the sinoatrial node. During the transition from rest to activity, sympathetic neurons stimulate these cells by activating β-adrenergic receptors and increasing intracellular cyclic adenosine monophosphate. The same signal transduction pathway is targeted by positive chronotropic drugs such as norepinephrine and dobutamine, which are used in the treatment of cardiogenic shock and severe heart failure. The cyclic adenosine monophosphate-sensitive hyperpolarization-activated current (If) in pacemaker cells is passed by hyperpolarization-activated cyclic nucleotide-gated cation channels and is critical for generating the autonomous heartbeat. In addition, this current has been suggested to play a central role in the chronotropic effect. Recent studies demonstrate that cyclic adenosine monophosphate-dependent regulation of HCN4 (hyperpolarization-activated cyclic nucleotide-gated cation channel isoform 4) acts to stabilize the heart rate, particularly during rapid rate transitions induced by the autonomic nervous system. The mechanism is based on creating a balance between firing and recently discovered nonfiring pacemaker cells in the sinoatrial node. In this way, hyperpolarization-activated cyclic nucleotide-gated cation channels may protect the heart from sinoatrial node dysfunction, secondary arrhythmia of the atria, and potentially fatal tachyarrhythmia of the ventricles. Here, we review the latest findings on sinoatrial node automaticity and discuss the physiological and pathophysiological role of HCN pacemaker channels in the chronotropic response and beyond.

Effectiveness and safety of ivabradine in Chinese patients with chronic heart failure: an observational study

AIMS

A therapeutic strategy for chronic heart failure (HF) is to lower resting heart rate (HR). Ivabradine is a well-known HR-lowering agent, but limited prospective data exist regarding its use in Chinese patients. This study aimed to evaluate the effectiveness and safety of ivabradine in Chinese patients with chronic HF.

METHODS AND RESULTS

This multicentre, single-arm, prospective, observational study enrolled Chinese patients with chronic HF. The primary outcome was change from baseline in HR at 1 and 6 months, measured by pulse counting. Effectiveness was also evaluated using laboratory tests, the Kansas City Cardiomyopathy Questionnaire (KCCQ) clinical summary score (CSS) and overall summary score (OSS), and New York Heart Association (NYHA) class. Treatment-emergent adverse events (TEAEs) were assessed. A post hoc analysis examined the effectiveness and safety of ivabradine combined with an angiotensin receptor-neprilysin inhibitor (ARNI) or beta-blocker. A total of 1003 patients were enrolled [mean age 54.4 ± 15.0 years, 773 male (77.1%), mean baseline HR 88.5 ± 11.3 b.p.m., mean blood pressure 115.7/74.4 ± 17.2/12.3 mmHg, mean left ventricular ejection fraction 30.9 ± 7.6%, NYHA Classes III and IV in 48.8% and 22.0% of patients, respectively]. HR decreased by a mean of 12.9 and 16.1 b.p.m. after 1 and 6 months, respectively (both P < 0.001). At Month 6, improvements in the KCCQ CSS and OSS of ≥5 points were observed in 72.1% and 74.1% of patients, respectively (both P < 0.001). Left ventricular ejection fraction increased by 12.1 ± 11.6 (P < 0.001), and 66.7% of patients showed improvement in NYHA class (P < 0.001). At Month 6, the overall proportion of patients in NYHA Classes III and IV was reduced to 13.5% and 2.1%, respectively. Serum brain natriuretic peptide (BNP) and N-terminal pro-BNP changed by -331.9 ng/L (-1238.6, -134.0) and -1113.8 ng/L (-2202.0, -297.2), respectively (P < 0.001). HR reductions and improvements in NYHA and KCCQ scores with ivabradine were similar with and without use of ARNIs or beta-blockers. Of 498 TEAEs in 296 patients (29.5%), 73 TEAEs in 55 patients (5.5%) were considered related to ivabradine [most frequent sinus bradycardia (n = 7) and photopsia (n = 7)]. TEAEs were reported in a similar number of patients in ARNI and beta-blocker subgroups (21.9-35.6%).

CONCLUSIONS

Ivabradine treatment reduced HR and improved cardiac function and health-related quality of life in Chinese patients with chronic HF. Benefits were seen irrespective of whether or not patients were also taking ARNIs or beta-blockers. Treatment was well tolerated with a similar profile to previous ivabradine studies.

Eligibility for vericiguat in a real-world heart failure population according to trial, guideline and label criteria: Data from the Swedish Heart Failure Registry

AIM

We investigated the eligibility for vericiguat in a real-world heart failure (HF) population based on trial, guideline and label criteria.

METHODS AND RESULTS

From the Swedish HF registry, 23 573 patients with HF with reduced ejection fraction (HFrEF) enrolled between 2000 and 2018, with a HF duration ≥6 months, were considered. Eligibility for vericiguat was calculated based on criteria from (i) the Vericiguat Global Study in Subjects with Heart Failure and Reduced Ejection Fraction (VICTORIA) trial; (ii) European and American guidelines on HF; (iii) product labelling according to the Food and Drug Administration and European Medicines Agency. Estimated eligibility for vericiguat in the trial, guidelines, and label scenarios was 21.4%, 47.4%, and 47.4%, respectively. Prior HF hospitalization within 6 months was the criterion limiting eligibility the most in all scenarios (met by 49.1% of the population). In the trial scenario, other criteria meaningfully limiting eligibility were elevated N-terminal pro-B-type natriuretic peptide levels and nitrate use. In all scenarios, eligibility was higher among patients hospitalized for HF at baseline (44.3% vs. 21.4% [trial scenario] and 97.3% vs. 47.4% [guideline/label scenarios] for hospitalized vs. non-hospitalized patients). Overall, eligible patients were older, had more severe HF, more comorbidities, and consequently higher cardiovascular mortality and HF hospitalization rates compared with ineligible patients across all scenarios.

CONCLUSION

In a large and contemporary real-world HFrEF cohort, we estimated that 21.4% of patients would be eligible for vericiguat according to the VICTORIA trial selection criteria, 47.4% based on guidelines and labelling. Eligibility for vericiguat translated into the selection of a population at high risk of morbidity/mortality.

Cardio-renal-metabolic syndrome: clinical features and dapagliflozin eligibility in a real-world heart failure cohort

AIMS

The Cardiovascular Outcomes Retrospective Data analysIS in Heart Failure (CORDIS-HF) is a single-centre retrospective study aimed to (i) clinically characterize a real-world population with heart failure (HF) with reduced (HFrEF) and mildly reduced ejection fraction (HFmrEF), (ii) evaluate impact of renal-metabolic comorbidities on all-cause mortality and HF readmissions, and (iii) determine patients' eligibility for sodium-glucose cotransporter 2 inhibitors (SGLT2is).

METHODS AND RESULTS

Using a natural language processing algorithm, clinical data of patients diagnosed with HFrEF or HFmrEF were retrospectively collected from 2014 to 2018. Mortality and HF readmission events were collected during subsequent 1 and 2 year follow-up periods. The predictive role of patients' baseline characteristics for outcomes of interest was assessed using univariate and multivariate Cox proportional hazard models. Kaplan-Meier analysis was used to determine if type 2 diabetes (T2D) and chronic kidney disease (CKD) impacted mortality and HF readmission rates. The European SGLT2i label criteria were used to assess patients' eligibility. The CORDIS-HF included 1333 HF patients with left ventricular ejection fraction (LVEF) < 50% (413 HFmrEF and 920 HFrEF), who were predominantly male (69%) with a mean [standard deviation (SD)] age of 74.7 (12.3) years. About one-half (57%) of patients presented CKD and 37% T2D. The use of guideline-directed medical therapy (GDMT) was high (76-90%). HFrEF patients presented lower age [mean (SD): 73.8 (12.4) vs. 76.7 (11.6) years, P < 0.05], higher incidence of coronary artery disease (67% vs. 59%, P < 0.05), lower systolic blood pressure [mean (SD): 123 (22.6) vs. 133 (24.0) mmHg, P < 0.05], higher N-terminal pro-hormone brain natriuretic peptide (2720 vs. 1920 pg/mL, P < 0.05), and lower estimated glomerular filtration rate [mean (SD): 51.4 (23.3) vs. 54.1 (22.3) mL/min/1.73 m2 , P < 0.05] than those with HFmrEF. No differences in T2D and CKD were detected. Despite optimal treatment, event rates for the composite endpoint of HF readmission and mortality were 13.7 and 8.4/100 patient years. The presence of T2D and CKD negatively impacted all-cause mortality [T2D: hazard ratio (HR) = 1.49, P < 0.01; CKD: HR = 2.05, P < 0.001] and hospital readmission events in all patients with HF. Eligibility for SGLT2is dapagliflozin and empagliflozin was 86.5% (n = 1153) and 97.9% (n = 1305) of the study population, respectively.

CONCLUSIONS

This study identified high residual risk for all-cause mortality and hospital readmission in real-world HF patients with LVEF < 50% despite GDMT. T2D and CKD aggravated the risk for these endpoints, indicating the intertwinement of HF with CKD and T2D. SGLT2i treatment that clinically benefits these different disease conditions can be an important driver to lower mortality and hospitalizations in this HF population.

Early administration of ivabradine in patients admitted for acute decompensated heart failure

BACKGROUND

Heart rate (HR) control is important in heart failure (HF) patients with reduced ejection fraction, and ivabradine is indicated for patients with chronic HF and sinus rhythm. However, ivabradine is limited in initiation of ivabradine at acute stage of HF.

MATERIALS AND METHODS

This multi-institutional retrospective study enrolled 30,639 patients who were admitted for HF from January 01, 2013 to December 31, 2018 at Chang Gung Memorial Hospitals. After applying selection criteria, the eligible patients were divided into ivabradine and non-ivabradine groups according to the initiation of ivabradine at the index hospitalization. HR, clinical outcomes including HF hospitalization, all-cause hospitalization, mortality, the composite of cardiovascular (CV) death or HF hospitalization and newly developed atrial fibrillation, and left ventricular ejection fraction (LVEF) and left atrium size were compared between the ivabradine and non-ivabradine groups after inverse probability of treatment weighting (IPTW) analysis after 12 months.

RESULTS

The HR at admission in the ivabradine group (n = 433) was 99.04 ± 20.69/min, compared to 86.99 ± 20.34/min in the non-ivabradine group (n = 9,601). After IPTW, HR was lower in the ivabradine group than that in the non-ivabradine group after 12 months (74.14 ± 8.53 vs. 81.23 ± 16.79 bpm, p = 0.079). However, there were no significant differences in HF hospitalization (HR = 1.02; 95% CI, 0.38-2.79), all-cause hospitalization (HR = 0.95; 95% CI, 0.54-1.68), mortality (HR = 0.87; 95% CI, 0.69-1.08), the composite of CV death or HF hospitalization (HR = 0.87; 95% CI, 0.69-1.08) and newly developed AF between the two groups. In addition, LVEF increased with time in both groups, but there were no significant differences during the observation period.

CONCLUSION

Ivabradine was beneficial in controlling HR when initiated in patients with acute stage of HF, but it did not seem to provide any benefits in reducing HF hospitalization, all-cause hospitalization, and mortality in 1 year after discharge.

Cost effectiveness analyses of pharmacological treatments in heart failure

In a rapidly growing and aging population, heart failure (HF) has become recognised as a public health concern that imposes high economic and societal costs worldwide. HF management stems from the use of highly cost-effective angiotensin converting enzyme inhibitors (ACEi) and β-blockers to the use of newer drugs such as sodium-glucose cotransporter-2 inhibitors (SGLT2i), ivabradine, and vericiguat. Modelling studies of pharmacological treatments that report on cost effectiveness in HF is important in order to guide clinical decision making. Multiple cost-effectiveness analysis of dapagliflozin for heart failure with reduced ejection fraction (HFrEF) suggests that it is not only cost-effective and has the potential to improve long-term clinical outcomes, but is also likely to meet conventional cost-effectiveness thresholds in many countries. Similar promising results have also been shown for vericiguat while a cost effectiveness analysis (CEA) of empagliflozin has shown cost effectiveness in HF patients with Type 2 diabetes. Despite the recent FDA approval of dapagliflozin and empagliflozin in HF, it might take time for these SGLT2i to be widely used in real-world practice. A recent economic evaluation of vericiguat found it to be cost effective at a higher cost per QALY threshold than SGLT2i. However, there is a lack of clinical or real-world data regarding whether vericiguat would be prescribed on top of newer treatments or in lieu of them. Sacubitril/valsartan has been commonly compared to enalapril in cost effectiveness analysis and has been found to be similar to that of SGLT2i but was not considered a cost-effective treatment for heart failure with reduced ejection fraction in Thailand and Singapore with the current economic evaluation evidences. In order for more precise analysis on cost effectiveness analysis, it is necessary to take into account the income level of various countries as it is certainly easier to allocate more financial resources for the intervention, with greater effectiveness, in high- and middle-income countries than in low-income countries. This review aims to evaluate evidence and cost effectiveness studies in more recent HF drugs i.e., SGLT2i, ARNi, ivabradine, vericiguat and omecamtiv, and gaps in current literature on pharmacoeconomic studies in HF.

Ivabradine in heart failure patients with reduced ejection fraction and history of paroxysmal atrial fibrillation

AIMS

Ivabradine is indicated for heart failure (HF) patients with reduced ejection fraction (HFrEF), but limited data are available with regards to the use of ivabradine in those with a history of paroxysmal atrial fibrillation (AF). To assess the effect of ivabradine in HFrEF patients with paroxysmal AF, we analysed heart failure (HF) hospitalization and mortality from multiple-centre registry database.

METHODS AND RESULTS

We conducted a multicentre observational matched cohort study, and this study enrolled patient with symptomatic HFrEF from 1 January 2015 to 31 December 2018 who had a history of paroxysmal AF in Chang Gung Memorial Hospital medical database in Taiwan. A total of 2042 patients were eligible for the study, of whom 887 were prescribed with ivabradine and 1115 were not. The primary outcome, including HF hospitalization and cardiovascular death, and individual outcome during the 12 month observation period were analysed after inverse probability of treatment weighting. The ivabradine group had significantly lower mean heart rate after 12 months follow-up than the non-ivabradine group (P < 0.05). The primary outcome was significantly higher in the ivabradine group than the non-ivabradine group after 12 months follow-up (hazard ratio [HR] = 1.58; 95% confidence interval [CI], 1.26-2.00, P < 0.001). Moreover, the ivabradine group had a significantly higher event rate of HF hospitalization (HR = 1.56; 95% CI, 1.40-1.75, P < 0.001) and HF death (HR = 1.67; 95% CI, 1.14-2.44, P = 0.009) than the non-ivabradine group.

CONCLUSIONS

Ivabradine treatment was associated with an increased risk of HF hospitalization in symptomatic HFrEF patients with a history of paroxysmal AF. Further prospective randomized studies are warranted.

Real-World Effectiveness of Ivabradine in Chinese Patients with Chronic Heart Failure: Interim Analysis of the POSITIVE Study

Background

Ivabradine improves cardiac function and clinical outcomes in chronic heart failure (HF) by reducing heart rate (HR), but there is a lack of real-world data on its effectiveness and safety in Chinese patients.

Methods

We designed a prospective, multicenter, observational study of Chinese adults with HF and left ventricular systolic dysfunction, resting HR ≥ 75 beats per minute (bpm), and an indication for ivabradine treatment. An interim analysis was performed using a cut-off date of 31 October 2019. The primary outcome was change in HR at 6 months after the initiation of ivabradine. Secondary endpoints included change in New York Heart Association (NYHA) functional class; quality of life (QoL), measured using the Kansas City Cardiomyopathy Questionnaire (KCCQ); and adverse events (AEs).

Results

Overall, 655 subjects were included in the interim analysis. Mean reduction in HR from baseline was 13.2 (95% confidence interval [CI] 11.2–15.2) bpm at Month 1, and 14.5 (95% CI 11.8–17.2) bpm at Month 6 (p < 0.001 for both changes). NYHA functional class and KCCQ scores improved significantly over time (p < 0.001 for all comparisons with baseline), indicating amelioration of symptoms and better QoL, respectively. Forty-four subjects (6.7%) reported a total of 60 ivabradine-related AEs, most frequently phosphenes and bradycardia (both n = 6, 0.9%).

Conclusion

Treatment with ivabradine for 6 months effectively reduced HR and improved functional class and QoL in Chinese patients with chronic HF. Treatment was well tolerated.

Clinical Trial Registration

ISRCTN11703380; registered on 8 November 2016.

Trends in survival of Swedish men and women with heart failure from 1987 to 2014: a population-based case-control study

AIMS

To compare trends in short-term and long-term survival of patients with heart failure (HF) compared with controls from the general population.

METHODS AND RESULTS

We used data from the Swedish National Inpatient Registry to identify all patients aged ≥18 years with a first recorded diagnosis of HF between 1 January 1987 and 31 December 2014 and compared them with controls matched on age and sex from the Total Population Register. We included 702 485 patients with HF and 1 306 183 controls. In patients with HF aged 18-64 years, short-term (29 days to 6 months) and long-term mortality (>11 years) decreased from 166 and 76.6 per 1000 person-years in 1987 to 2000 to 99.6 and 49.4 per 1000 person-years, respectively, in 2001 to 2014. During the same period, mortality improved marginally, in those aged ≥65 years: short-time mortality from 368.8 to 326.2 per 1000 person-years and long-term mortality from 219.6 to 193.9 per 1000 person-years. In 1987-2000, patients aged <65 years had more than three times higher risk of dying at 29 days to 6 months, with an hazard ratio (HR) of 3.66 [95% confidence interval (CI) 3.46-3.87], compared with controls (P < 0.0001) but substantially higher in 2001-2014 with an HR of 11.3 (95% CI 9.99-12.7, P < 0.0001). HRs for long-term mortality (6-10 and >11 years) increased moderately from 2.49 (95% CI 2.41-2.57) and 3.16 (95% CI 3.07-3.24) in 1987-2000 to 4.35 (95% CI 4.09-4.63) and 4.11 (95% CI 3.49-4.85) in 2001-2014, largely because survival among controls improved more than that among patients with HF (P < 0.0001).

CONCLUSIONS

Absolute survival improved in HF patients aged <65 years, but only marginally so in those aged ≥65 years. Compared with controls, both short-term and long-term relative risk of dying increased, especially in younger patients with HF.

Sodium-glucose co-transporter-2 inhibitors eligibility in patients with heart failure with reduced ejection fraction

BACKGROUND

The sodium-glucose co-transporter-2 (SGLT2) inhibitors dapagliflozin and empagliflozin have been demonstrated to reduce adverse cardiovascular outcomes in patients with heart failure with reduced ejection fraction (HFrEF). Limited data are available characterizing the generalizability of SGLT2 inhibitors treatment in the clinical practice. The aim of the study was to evaluate the proportion of outpatients with HFrEF that would be eligible for SGLT2 inhibitors in a contemporary real-world population.

METHODS

We retrospectively evaluated patients with chronic stable HFrEF followed-up at the HF outpatient clinic of our institution. Patients' eligibility was assessed according to the entry criteria of DAPA-HF (dapagliflozin) and EMPEROR-Reduced (empagliflozin) trials and to US Food and Drug Administration (FDA) label criteria (only dapagliflozin).

RESULTS

A total of 441 HFrEF patients was enrolled. According to the major inclusion and exclusion criteria from DAPA-HF and EMPEROR-Reduced trials, 198 (45%) patients would be candidates for initiation of both dapagliflozin and empagliflozin, 61 (14%) would be eligible only to dapagliflozin and 23 (5%) only to empagliflozin, without significant differences between diabetic and non-diabetic patients (p = 0.23). Among patients not suitable for gliflozins treatment (159 patients; 36%), the major determinant of ineligibility was the failure to achieve the predefined NT-proBNP inclusion threshold. Excluding NTproBNP as per FDA label criteria, dapagliflozin eligibility increased to 86%.

CONCLUSIONS

In our real-world analysis a large proportion of HFrEF patients would be candidates for initiation of SGLT2 inhibitors, supporting its broad generalizability in clinical practice. This would be expected to reduce morbidity and mortality in eligible patients.

Ivabradine: A Potential Therapeutic for Children With Refractory SVT

Background: In April 2015, ivabradine was approved by the Food and Drug Administration for the treatment of patients with coronary artery disease and heart failure (HF). The use of this medication has been linked with improved clinical outcomes and reduced rates of hospitalization in patients with symptomatic HF and a baseline heart rate of 70 bpm and above. Nonetheless, little is known about the use of ivabradine in pediatric patients with supraventricular tachycardia (SVT). This use is not well-studied and is only endorsed by a few case reports and case series.

Aim: This study discusses the off-label utilization of ivabradine in pediatric patients with SVT, and highlights its efficacy in treating treatment-resistant (refractory) SVT.

Methods: We conducted a retrospective single-center observational study involving pediatric patients with SVT treated at our center between January 2016 and October 2020. We identified the total number of patients with SVT, and the number of patients with refractory SVT treated with Ivabradine. Similarly, we performed a thorough review of the databases of PubMed, Medline and Google Scholar to compare the clinical course of our patients to those described in the literature.

Results: Between January 2016 and October 2020, 79 pediatric patients with SVT were seen and treated at our center. A treatment-resistant SVT was noted only in three patients (4%). Ivabradine was used in these patients as a single or combined therapy. The rest (96%) were successfully treated with conventional anti-arrhythmics such as β-blockers, flecainide, and other approved medications. In the ivabradine group, successful reversal to sinus rhythm was achieved in two of the three patients (66%), one patient was treated with a combination therapy of amiodarone and ivabradine, and the other patient was treated only with ivabradine.

Conclusion: Overall, promissory results are associated with the use of ivabradine in pediatric patients with refractory SVT. Ivabradine appears to be a safe and well-tolerated medication that can induce adequate suppression of SVT, complete reversal to sinus rhythm, and effective enhancement of left ventricular function.

Use of Preoperative Single Dose Ivabradine for Perioperative Hemodynamic Stabilization During Non-Cardiac Elective Surgery Under General Anaesthesia: A Pilot Study

BACKGROUND

Peri-anesthetic hemodynamic fluctuations during non-cardiac surgeries are sometimes of serious consequences and associated with increased morbidity and mortality, especially in undiagnosed vulnerable patients. Currently used drugs like β-blocker, α2 agonist or sedative analgesic have their own limitations like combined negative ionotropic and chronotropic action, and unwanted bradycardia associated with hypotension, respectively. In this context, ivabradine has been used extensively in cases of cardiac failure, myocardial ischemia and cardiomyopathies for its funny channel associated dependable heart rate reducing property. Hence, for the first time, in search of a better agent for perioperative hemodynamic stabilization, the present study evaluated the role of ivabradine in patients undergoing non-cardiac surgeries.

METHODS

This was a prospective, observer blind, randomized, interventional pilot study, conducted among 50 patients belonging undergoing elective abdominal laparoscopic surgeries, under general anesthesia. The study group patients received ivabradine tablet 7.5 mg, 2 h before scheduled time of surgery with a sip of water. All the patients received standardized balanced general anesthesia as practiced in our institute with all standard monitoring with additional minimum alveolar concentration (MAC) monitoring to ensure an adequate depth of anesthesia, and neuromuscular monitoring to ensure adequate and standard muscle relaxation. Hemodynamic stability of the groups was tested by comparing them at time points like induction, incision and operation, and extubation. Mean values of heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP) and mean arterial pressure (MAP) were compared between groups, and also for variation with lapse of time, using RMANOVA analysis, using baseline parameters as covariate so as to standardize them.

RESULTS

On multivariate analysis using Wilk's lambda multivariate test, there was a statistically significant difference (F = 3.587, P = 0.036) in HR between the groups with time, while no significant difference of SBP, DBP and MAP between the groups with time.

CONCLUSIONS

The study revealed a significant attenuation of HR response to stressful events like laryngoscopy, intubation and surgical incision with ivabradine. Also, a good intraoperative protection against cardiovascular ischemic and arrhythmic episodes in perioperative period was achieved with this drug ivabradine.

Rad-GTPase contributes to heart rate via L-type calcium channel regulation

Sinoatrial node cardiomyocytes (SANcm) possess automatic, rhythmic electrical activity. SAN rate is influenced by autonomic nervous system input, including sympathetic nerve increases of heart rate (HR) via activation of β-adrenergic receptor signaling cascade (β-AR). L-type calcium channel (LTCC) activity contributes to membrane depolarization and is a central target of β-AR signaling. Recent studies revealed that the small G-protein Rad plays a central role in β-adrenergic receptor directed modulation of LTCC. These studies have identified a conserved mechanism in which β-AR stimulation results in PKA-dependent Rad phosphorylation: depletion of Rad from the LTCC complex, which is proposed to relieve the constitutive inhibition of CaV1.2 imposed by Rad association. Here, using a transgenic mouse model permitting conditional cardiomyocyte selective Rad ablation, we examine the contribution of Rad to the control of SANcm LTCC current (ICa,L) and sinus rhythm. Single cell analysis from a recent published database indicates that Rad is expressed in SANcm, and we show that SANcm ICa,L was significantly increased in dispersed SANcm following Rad silencing compared to those from CTRL hearts. Moreover, cRadKO SANcm ICa,L was not further increased with β-AR agonists. We also evaluated heart rhythm in vivo using radiotelemetered ECG recordings in ambulating mice. In vivo, intrinsic HR is significantly elevated in cRadKO. During the sleep phase cRadKO also show elevated HR, and during the active phase there is no significant difference. Rad-deletion had no significant effect on heart rate variability. These results are consistent with Rad governing LTCC function under relatively low sympathetic drive conditions to contribute to slower HR during the diurnal sleep phase HR. In the absence of Rad, the tonic modulated SANcm ICa,L promotes elevated sinus HR. Future novel therapeutics for bradycardia targeting Rad - LTCC can thus elevate HR while retaining βAR responsiveness.

CCS/CHFS Heart Failure Guidelines Update: Defining a New Pharmacologic Standard of Care for Heart Failure With Reduced Ejection Fraction

In this update of the Canadian Cardiovascular Society heart failure (HF) guidelines, we provide comprehensive recommendations and practical tips for the pharmacologic management of patients with HF with reduced ejection fraction (HFrEF). Since the 2017 comprehensive update of the Canadian Cardiovascular Society guidelines for the management of HF, substantial new evidence has emerged that has informed the care of these patients. In particular, we focus on the role of novel pharmacologic therapies for HFrEF including angiotensin receptor-neprilysin inhibitors, sinus node inhibitors, sodium glucose transport 2 inhibitors, and soluble guanylate cyclase stimulators in conjunction with other long established HFrEF therapies. Updated recommendations are also provided in the context of the clinical setting for which each of these agents might be prescribed; the potential value of each therapy is reviewed, where relevant, for chronic HF, new onset HF, and for HF hospitalization. We define a new standard of pharmacologic care for HFrEF that incorporates 4 key therapeutic drug classes as standard therapy for most patients: an angiotensin receptor-neprilysin inhibitor (as first-line therapy or after angiotensin converting enzyme inhibitor/angiotensin receptor blocker titration); a β-blocker; a mineralocorticoid receptor antagonist; and a sodium glucose transport 2 inhibitor. Additionally, many patients with HFrEF will have clinical characteristics for which we recommended other key therapies to improve HF outcomes, including sinus node inhibitors, soluble guanylate cyclase stimulators, hydralazine/nitrates in combination, and/or digoxin. Finally, an approach to management that integrates prioritized pharmacologic with nonpharmacologic and invasive therapies after a diagnosis of HFrEF is highlighted.

Applicability of US Food and Drug Administration Labeling for Dapagliflozin to Patients With Heart Failure With Reduced Ejection Fraction in US Clinical Practice: The Get With the Guidelines-Heart Failure (GWTG-HF) Registry

Importance

In May 2020, dapagliflozin was approved by the US Food and Drug Administration (FDA) as the first sodium-glucose cotransporter 2 inhibitor for heart failure with reduced ejection fraction (HFrEF), based on the Dapagliflozin and Prevention of Adverse Outcomes in Heart Failure (DAPA-HF) trial. Limited data are available characterizing the generalizability of dapagliflozin to US clinical practice.

Objective

To evaluate candidacy for initiation of dapagliflozin based on the FDA label among contemporary patients with HFrEF in the US.

Design, Setting, and Participants

This cohort study included 154 714 patients with HFrEF (left ventricular ejection fraction ≤40%) hospitalized at 406 sites in the Get With the Guidelines-Heart Failure (GWTG-HF) registry admitted between January 1, 2014, and September 30, 2019. Patients who left against medical advice, transferred to an acute care facility or to hospice, or had missing data were excluded. The FDA label (which excluded patients with an estimated glomerular filtration rate [eGFR] <30 mL/min/1.73 m2, those undergoing dialysis, and those with type 1 diabetes) was applied to the GWTG-HF registry sample. Data analyses were conducted from April 1 to June 30, 2020.

Main Outcomes and Measures

The proportion of patients hospitalized with HFrEF who would be candidates for dapagliflozin under the FDA label.

Results

Among 154 714 patients hospitalized with HFrEF, 125 497 (81.1%; 83 481 men [66.5%]; mean [SD] age, 68 [15] years) would be candidates for dapagliflozin according to the FDA label. Across 355 sites with patients with 10 or more hospitalizations, the median proportion of candidates for dapagliflozin according to the FDA label was 81.1% (interquartile range, 77.8%-84.6%) at each site. This proportion was similar across all study years (interquartile range, 80.4%-81.7%) and was higher among those without type 2 diabetes than with type 2 diabetes (85.5% vs 75.6%). Among GWTG-HF participants, the most frequent reason for not meeting the FDA label criteria was eGFR less than 30 mL/min/1.73 m2 at discharge (18.5%). Among 75 654 patients with available paired admission and discharge data, 14.2% had an eGFR less than 30 mL/min/1.73 m2 at both time points, while 3.8% developed an eGFR less than 30 mL/min/1.73 m2 by discharge. Although there were more older adults, women, and Black patients in the GWTG-HF registry than in the DAPA-HF trial, most clinical characteristics were qualitatively similar between the 2 groups. Compared with the DAPA-HF trial cohort, there was lower use of evidence-based HF therapies among patients in GWTG-HF.

Conclusions and Relevance

These data from a large, contemporary US registry of patients hospitalized with heart failure suggest that 4 of 5 patients with HFrEF (with or without type 2 diabetes) would be candidates for initiation of dapagliflozin, supporting its broad generalizability to US clinical practice.

Ivabradine in Cardiovascular Disease Management Revisited: a Review

Ivabradine is a unique agent that is distinct from beta-blockers and calcium channel blockers as it reduces heart rate without affecting myocardial contractility or vascular tone. Ivabradine is a use-dependent inhibitor targeting the sinoatrial node. It is approved for use in the United States as an adjunct therapy for heart rate reduction in patients with heart failure with reduced ejection fraction. In this scenario, ivabradine has demonstrated improved clinical outcomes due to reduction in heart failure readmissions. However, there has been conflicting evidence from prospective studies and randomized controlled trials for its use in stable ischemic heart disease regarding efficacy in symptom reduction and mortality benefit. Ivabradine may also play a role in the treatment of patients with inappropriate sinus tachycardia, who often cannot tolerate beta-blockers and/or calcium channel blockers. In this review, we highlight the evidence for the nuances of using ivabradine in heart failure, stable ischemic heart disease, and inappropriate sinus tachycardia to raise awareness for its vital role in the treatment of select populations.

How Heart Rate Should Be Controlled in Patients with Atherosclerosis and Heart Failure

PURPOSE OF REVIEW

Resting heart rate is an independent risk factor for all-cause and cardiovascular mortality in patients with heart failure. The main objectives are to discuss the prognosis of heart rate, its association with coronary atherosclerosis, and the modalities of control of the heart rate in sinus rhythm and in the rhythm of atrial fibrillation in patients with chronic heart failure.

RECENT FINDINGS

As a therapeutic option for control heart rate, medications such as beta-blockers, digoxin, and finally ivabradine have been studied. Non-dihydropyridine calcium channel blockers are contraindicated in patients with heart failure and reduced ejection fraction. The influence of the magnitude of heart rate reduction and beta-blocker dose on morbidity and mortality will be discussed. Regarding the patients with heart failure and atrial fibrillation, there are different findings in heart rate control with the use of a beta-blocker. Patients eligible for ivabradine have clinical benefits and increased ejection fraction. Vagal nerve stimulation has low efficacy for the control of heart rate. Complementary therapies such as tai chi and yoga showed no effect on heart rate. In this review, we discuss the main therapeutic options for the control of heart rate in patients with atherosclerosis and heart failure. More research is needed to examine the effects of therapeutic options for heart rate control in different population types, as well as their effects on clinical outcomes and impact on morbidity and mortality.